NM_000518.5:c.76_92+27delGGTGAGGCCCTGGGCAGGTTGGTATCAAGGTTACAAGACAGGTT

Variant names:

• chr11-5226902-AAACCTGTCTTGTAACCTTGATACCAACCTGCCCAGGGCCTCACC-A
• rs63751076
• NM_000518.5:c.76_92+27delGGTGAGGCCCTGGGCAGGTTGGTATCAAGGTTACAAGACAGGTT

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PP5_Moderate

The NM_000518.5(HBB):​c.76_92+27delGGTGAGGCCCTGGGCAGGTTGGTATCAAGGTTACAAGACAGGTT​(p.Gly26fs) variant causes a frameshift, splice donor, splice region, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type DEL_BIG, and the frequency of such variant types in population databases may be underestimated and unreliable. Variant has been reported in ClinVar as Likely pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. G26G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: HBB NM_000518.5 frameshift, splice_donor, splice_region, intron
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:3
• Conservation: PhyloP100: 0.304
• Publications: 2 publications found

Genes affected

HBB (HGNC:4827): (hemoglobin subunit beta) The alpha (HBA) and beta (HBB) loci determine the structure of the 2 types of polypeptide chains in adult hemoglobin, Hb A. The normal adult hemoglobin tetramer consists of two alpha chains and two beta chains. Mutant beta globin causes sickle cell anemia. Absence of beta chain causes beta-zero-thalassemia. Reduced amounts of detectable beta globin causes beta-plus-thalassemia. The order of the genes in the beta-globin cluster is 5'-epsilon -- gamma-G -- gamma-A -- delta -- beta--3'. [provided by RefSeq, Jul 2008]

HBB Gene-Disease associations (from GenCC):

• dominant beta-thalassemia

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
• hemoglobin M disease

  Inheritance: AD Classification: DEFINITIVE, MODERATE, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, ClinGen
• beta thalassemia

  Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
• beta-thalassemia HBB/LCRB

  Inheritance: AR, SD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
• sickle cell disease and related diseases

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• erythrocytosis, familial, 6

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• Heinz body anemia

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• sickle cell disease

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
• hereditary persistence of fetal hemoglobin-beta-thalassemia syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• beta-thalassemia intermedia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• beta-thalassemia major

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• delta-beta-thalassemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hemoglobin C disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hemoglobin C-beta-thalassemia syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hemoglobin E disease

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hemoglobin E-beta-thalassemia syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary persistence of fetal hemoglobin-sickle cell disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• sickle cell-beta-thalassemia disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• sickle cell-hemoglobin c disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• sickle cell-hemoglobin d disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• sickle cell-hemoglobin E disease syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000298932 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 268 pathogenic variants in the truncated region.
• PP5: Variant 11-5226902-AAACCTGTCTTGTAACCTTGATACCAACCTGCCCAGGGCCTCACC-A is Pathogenic according to our data. Variant chr11-5226902-AAACCTGTCTTGTAACCTTGATACCAACCTGCCCAGGGCCTCACC-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 15445.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HBB	NM_000518.5	c.76_92+27delGGTGAGGCCCTGGGCAGGTTGGTATCAAGGTTACAAGACAGGTT	p.Gly26fs	frameshift_variant, splice_donor_variant, splice_region_variant, intron_variant	Exon 1 of 3	ENST00000335295.4	NP_000509.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HBB	ENST00000335295.4	c.76_92+27delGGTGAGGCCCTGGGCAGGTTGGTATCAAGGTTACAAGACAGGTT	p.Gly26fs	frameshift_variant, splice_donor_variant, splice_region_variant, intron_variant	Exon 1 of 3	1	NM_000518.5	ENSP00000333994.3

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, single submitter

Submissions by phenotype

Beta zero thalassemia Pathogenic:1

Mar 01, 1984

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Hemoglobinopathy Pathogenic:1

Jun 05, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: HBB c.76_92+27del44 is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material, in addition to removing part of the coding sequence of exon 1. Several computational tools predict a significant impact on normal splicing: Three predict the variant abolishes a canonical 5' splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 251226 control chromosomes (gnomAD). c.76_92+27del44 has been reported in the literature in an individual affected with Beta Thalassemia who was compound heterozygous with another likely pathogenic variant (Gonzalez-Redondo_1989). These data suggest the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 2753736). One submitter has provided a clinical-significance assessment for this variant to ClinVar after 2014, and classified it as pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

beta Thalassemia Pathogenic:1

Nov 25, 2019

The ITHANET community portal, The Cyprus Institute of Neurology and Genetics

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.30
Mutation Taster		=1/199	disease causing (ClinVar)

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs63751076; hg19: chr11-5248132;